Maca is a vegetable that has been cultivated as a root crop for at least 2,000 years. It can be found wild in Peru, Bolivia, Paraguay, and Argentina, but has primarily been cultivated in the highlands of the Peruvian Andes. Because of its ability to grow in harsh climates at high-altitude, maca is an important staple food for native populations in the Peruvian highlands. It is highly nutritious with about 11% protein content and can be baked, roasted, prepared as a porridge, and has been used for making a fermented drink.

Traditionally, maca has also been used to relieve stress, as an aphrodisiac, and for fertility enhancement in both males and females. Recently, commercial maca products have gained popularity in areas outside of South America as dietary supplements, with claims of boosting energy, enhancing fertility, balancing hormones, acting as an aphrodisiac, and enhancing sexual performance. However, evidence to support these claims is weak.

Natives of the central Andes do not use fresh maca. It is considered harmful. When maca is harvested, the roots are dried by exposing them to sunlight for 4-6 days. After they have been dried, they can be stored in cool, dark places for several years. For consumption, the dried roots are rehydrated by boiling them in water until they are soft. Maca is also referred to as Peruvian ginseng, although it is not closely related to ginseng.

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

GRADE *

Traditionally in Peru, maca has been used as an aphrodisiac. Maca could improve sexual desire in healthy men independent of changes in mood, or serum testosterone, and estradiol levels. Higher quality studies are needed in this area, in both men and women.

C

Traditionally, maca has been used in Peru to enhance fertility. One study did not demonstrate that maca ingestion could change levels of luteinizing hormone, follicle-stimulating hormone, prolactin, hydroxyprogesterone, testosterone, or estradiol. Additional study is needed before a firm conclusion can be made.

C

Maca has been traditionally used in Peru to enhance fertility of both people and animals. Maca may improve semen quality, however, additional study is needed to confirm this finding.

C

* Key to grades

A: Strong scientific evidence for this useB: Good scientific evidence for this useC: Unclear scientific evidence for this useD: Fair scientific evidence for this use (it may not work)F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

Maca is likely safe when consumed by healthy adults in doses of 1,500-3,000 milligrams per day for up to four months as an aphrodisiac or to improve spermatogenesis, however, there is no proven effective dose for maca. Traditionally, up to 6,000 milligrams or more per day in divided doses has been used. Root powder containing 2,800 milligrams of maca root placed in 8 ounces of water has also been used up to three times daily. Commercially prepared concentrated extracts containing 450 milligrams taken twice daily has been used as well.

Common dietary consumption in native populations is greater than 100 grams, or equivalent to greater than 1.4g per kilogram, daily.

Children (younger than 18 years)

There is no proven safe or effective dose of maca, and use in children is not recommended.

Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid in individuals with a known allergy or hypersensitivity to maca (Lepidium meyenii).

Side Effects and Warnings

Available studies in humans have only been performed on male subjects. In these trials, no side effects were noted and maca was generally considered safe. Maca has not been studied in women.

Maca may cause changes in some sex hormones, although animal studies have demonstrated conflicting results. Preliminary evidence from studies in humans has failed to show that maca induces changes in luteinizing hormone, follicle stimulating hormone, prolactin, testosterone, and estradiol. However, use cautiously in patients with hormone responsive cancers such as breast cancer, or prostate cancer, and patients who are using birth control pills due to the potential effects of maca on sex hormone regulation.

Consumption of large amounts of maca may cause bloating and flatulence. Consumption of fresh maca may cause stomach pain.

The use of maca may increase leukocytes.

The use of maca may decrease PT/INR values in patients being monitored for anticoagulation therapy.

Maca may also lead to stimulation of the central nervous system. Use cautiously in patients with hypertension (high blood pressure), due to the possibility of central nervous system stimulation.

Pregnancy and Breastfeeding

Maca is not recommended in pregnant or breastfeeding women due to a lack of available scientific evidence.

Plants in the Brassicaceae family, such as maca, are often rich in vitamin K. Maca may lower PT/INR values and decrease the effect of aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin®) or heparin, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).

Maca may act as a stimulant and cause hypertension (high blood pressure). Patients taking medication for high blood pressure, or those taking other stimulant medications, should consult with a qualified healthcare professional, including a pharmacist, before combining therapies.

Maca may alter the levels of sex hormones, and may interfere with the effects of hormone replacement therapy or birth control pills. Caution is advised.

Interactions with Herbs and Dietary Supplements

Plants in the Brassicaceae family, such as maca, are often rich in vitamin K. Maca may lower PT/INR values and decrease the effect of herbs and supplements that are believed to have anticoagulant effects, such as Ginkgo biloba, garlic, or saw palmetto.

Maca may act as a stimulant and cause hypertension (high blood pressure). Patients taking herbs or supplements for high blood pressure, or those taking other stimulants, should consult with a qualified healthcare professional, including a pharmacist, before combining therapies.

Maca may alter the levels of sex hormones, and may interfere with the effects of herbs or supplements with hormone effects, such as St. John's wort or chasteberry.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.